Optimizing radio frequency (RF) coverage in remote unit coverage areas in a wireless distribution system (WDS)

ABSTRACT

Embodiments of the disclosure relate to optimizing radio frequency (RF) coverage in remote unit coverage areas in a wireless distribution system (WDS). A control circuit is configured to selectively determine at least one selected remote unit group comprising two or more remote units selected from a plurality of remote units in the WDS. A first remote unit in the selected remote unit group is configured to transmit an RF signal. The control circuit is configured to determine a first prediction deviation and a second prediction deviation, respectively. The control circuit determines correction factor(s) for selected correction point(s) based on the first prediction deviation and the second prediction deviation. The control circuit optimizes RF coverage in coverage area(s) based on the determined correction factor(s), thus improving RF performance and capacity of the WDS.

PRIORITY APPLICATION

This application claims the benefit of priority under 35 U.S.C. §120 ofU.S. application Ser. No. 15/263,999 filed on Sep. 13, 2016, the contentof which is relied upon and incorporated herein by reference in itsentirety.

BACKGROUND

The disclosure relates generally to a wireless distribution system(WDS), and more particularly to optimizing radio frequency (RF) coveragein remote unit coverage areas in a WDS network.

Wireless customers are increasingly demanding digital data services,such as streaming video signals. At the same time, some wirelesscustomers use their wireless communications devices in areas that arepoorly serviced by conventional cellular networks, such as insidecertain buildings or areas where there is little cellular coverage. Oneresponse to the intersection of these two concerns has been the use ofWDSs. WDSs include remote units configured to receive and transmitcommunications signals to client devices within the antenna range of theremote units. WDSs can be particularly useful when deployed insidebuildings or other indoor environments where the wireless communicationsdevices may not otherwise be able to effectively receive RF signals froma signal source.

In this regard, FIG. 1 illustrates distribution of communicationservices to remote coverage areas 100(1)-100(N) of a WDS 102 provided inthe form of a DAS, wherein ‘N’ is the number of remote coverage areas.These communication services can include cellular services, wirelessservices, such as RF identification (RFID) tracking, Wireless Fidelity(Wi-Fi), local area network (LAN), wireless LAN (WLAN), wirelesssolutions (Bluetooth, Wi-Fi Global Positioning System (GPS)signal-based, and others) for location-based services, and combinationsthereof, as examples. The remote coverage areas 100(1)-100(N) may beremotely located. In this regard, the remote coverage areas100(1)-100(N) are created by and centered on remote units 104(1)-104(N)connected to a head-end equipment (HEE) 106 (e.g., a head-endcontroller, a head-end unit, or a central unit). The HEE 106 may becommunicatively coupled to a signal source 108, for example, a basetransceiver station (BTS) or a baseband unit (BBU). In this regard, theHEE 106 receives downlink communications signals 110D from the signalsource 108 to be distributed to the remote units 104(1)-104(N). Theremote units 104(1)-104(N) are configured to receive the downlinkcommunications signals 110D from the HEE 106 over a communicationsmedium 112 to be distributed to the respective remote coverage areas100(1)-100(N) of the remote units 104(1)-104(N). In a non-limitingexample, the communications medium 112 may be a wired communicationsmedium, a wireless communications medium, or an optical fiber-basedcommunications medium. Each of the remote units 104(1)-104(N) mayinclude an RF transmitter/receiver and a respective antenna114(1)-114(N) operably connected to the RF transmitter/receiver towirelessly distribute the communication services to client devices 116within the respective remote coverage areas 100(1)-100(N). The remoteunits 104(1)-104(N) are also configured to receive uplink communicationssignals 110U from the client devices 116 in the respective remotecoverage areas 100(1)-100(N) to be distributed to the signal source 108.The size of each of the remote coverage areas 100(1)-100(N) isdetermined by the amount of RF power transmitted by the respectiveremote units 104(1)-104(N), receiver sensitivity, antenna gain, and RFenvironment, as well as by RF transmitter/receiver sensitivity of theclient devices 116. The client devices 116 usually have a fixed maximumRF receiver sensitivity, so that the above-mentioned properties of theremote units 104(1)-104(N) mainly determine the size of the respectiveremote coverage areas 100(1)-100(N).

As previously discussed, the remote units 104(1)-104(N) are configuredto wirelessly distribute the communication services within the remotecoverage areas 100(1)-100(N). During design or initial deployment of theWDS 102, the transmission/reception range of remote coverage areas100(1)-100(N) may be estimated based on calculation and/or simulationtools. The estimated transmission/reception range may affect how the WDS102 is installed and how the remote units 104(1)-104(N) are deployed toprovide the desired remote coverage areas 100(1)-100(N). However, theremote coverage areas 100(1)-100(N) may not be estimated with perfectaccuracy due to difficulty in accurately predicting RF characteristicsin a real world environment. For instance, RF signal attenuation causedby walls, floors, and/or ceilings, RF signal reflection coefficient,and/or actual radiation pattern of the antennas 114(1)-114(N) cansignificantly impact the accuracy of the remote coverage areas100(1)-100(N). In this regard, it may be desirable to optimize RFcoverage in the remote coverage areas 100(1)-100(N) after the WDS 102 isdeployed.

No admission is made that any reference cited herein constitutes priorart. Applicant expressly reserves the right to challenge the accuracyand pertinency of any cited documents.

SUMMARY

Embodiments of the disclosure relate to optimizing radio frequency (RF)coverage in remote unit coverage areas in a wireless distribution system(WDS). Before a WDS is initially deployed, the placement design ofremote units in the WDS is based on predicted remote unit coverage areas(i.e., the transmission/reception coverage areas) from calculationsand/or simulations. However, the predicted remote unit coverage areasmay be different from actual remote unit coverage areas establishedafter deployment, because RF characteristics are difficult to factorinto the calculations and/or simulations due to potential signalobstruction elements (e.g., walls, floors, furniture, etc.). Hence, tooptimize RF coverage in the remote unit coverage areas after the WDS isdeployed, in certain aspects disclosed herein, a control circuit isprovided in the WDS and communicatively coupled to the remote unitsforming the remote unit coverage areas. The control circuit may beprovided in a central unit or located in one or more other components inthe WDS as examples. The control circuit is configured to selectivelydetermine at least one selected remote unit group including two or moreremote units selected from the remote units in the WDS. A remote unit inthe selected remote unit group is configured to transmit at least one RFsignal to the other remote units in the selected remote unit group todetermine prediction deviations (e.g., power prediction deviations)based on respective received RF signals. The control circuit isconfigured to determine one or more correction factors for one or moreselected correction points located within an area defined by theselected remote unit group based on the prediction deviations tooptimize RF coverage in the remote unit coverage areas serviced by theremote units in the selected remote unit group by correction factors.The correction factors can then be used to adjust one or more of theremote units to change the remote unit coverage areas with improvedaccuracy, thus improving RF performance and capacity of the WDS. Bydefining an appropriate number of selected remote unit groups involvingdifferent combinations of the remote units in the WDS, it is possible tooptimize RF coverage in all of the remote unit coverage areas in theWDS. As a result, overall RF performance and capacity of the WDS may beimproved.

One embodiment of the disclosure relates to a WDS. The WDS comprises aplurality of remote units. The plurality of remote units is configuredto receive a plurality of downlink communications signals from a centralunit over a plurality of downlink communications mediums and distributethe plurality of downlink communications signals in a plurality ofremote unit coverage areas, respectively. The plurality of remote unitsis also configured to receive a plurality of uplink communicationssignals in the plurality of remote unit coverage areas and provide theplurality of uplink communications signals to the central unit over aplurality of uplink communications mediums, respectively. The WDS alsocomprises a control circuit communicatively coupled to the plurality ofremote units. For at least one selected remote unit group comprising twoor more remote units among the plurality of remote units, the controlcircuit is configured to instruct a first remote unit in the at leastone selected remote unit group to transmit at least one RF signal. Thecontrol circuit is also configured to instruct a second remote unit inthe at least one selected remote unit group to receive the at least oneRF signal. The control circuit is also configured to determine a firstprediction deviation at the second remote unit based on a differencebetween the at least one RF signal received at the second remote unitand the at least one RF signal predicted to be received at the secondremote unit. The control circuit is also configured to instruct a thirdremote unit in the at least one selected remote unit group to receivethe at least one RF signal. The control circuit is also configured todetermine a second prediction deviation at the third remote unit basedon a difference between the at least one RF signal received at the thirdremote unit and the at least one RF signal predicted to be received atthe third remote unit. The control circuit is also configured todetermine one or more correction factors for one or more selectedcorrection points located within an area defined by the at least oneselected remote unit group based on the first prediction deviation andthe second prediction deviation.

Another embodiment of the disclosure relates to a method for optimizingRF coverage in remote unit coverage areas in a WDS. For at least oneselected remote unit group comprising two or more remote units among aplurality of remote units in the WDS, the method comprises instructing afirst remote unit in the at least one selected remote unit group totransmit at least one RF signal. The method also comprises instructing asecond remote unit in the at least one selected remote unit group toreceive the at least one RF signal. The method also comprisesdetermining a first prediction deviation at the second remote unit basedon a difference between the at least one RF signal received at thesecond remote and the at least one RF signal predicted to be received atthe second remote unit. The method also comprises instructing a thirdremote unit in the at least one selected remote unit group to receivethe at least one RF signal. The method also comprises determining asecond prediction deviation at the third remote unit based on adifference between the at least one RF signal received at the thirdremote unit and the at least one RF signal predicted to be received atthe third remote unit. The method also comprises determining one or morecorrection factors for one or more selected correction points locatedwithin an area defined by the at least one selected remote unit groupbased on the first prediction deviation and the second predictiondeviation.

Additional features and advantages will be set forth in the detaileddescription which follows and, in part, will be readily apparent tothose skilled in the art from the description or recognized bypracticing the embodiments as described in the written description andclaims hereof, as well as the appended drawings.

It is to be understood that both the foregoing general description andthe following detailed description are merely exemplary and are intendedto provide an overview or framework to understand the nature andcharacter of the claims.

The accompanying drawings are included to provide a furtherunderstanding of the disclosure, and are incorporated in and constitutea part of this specification. The drawings illustrate one or moreembodiment(s), and together with the description serve to explainprinciples and operation of the various embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an exemplary wireless distributionsystem (WDS);

FIG. 2 is a schematic diagram of an exemplary WDS in which a controlcircuit is configured to optimize radio frequency (RF) coverage in aplurality of remote unit coverage areas in the WDS based on RF signalpower levels measured in selected remote unit coverage areas among theremote unit coverage areas;

FIG. 3 is a schematic diagram providing an exemplary illustration of atleast one selected remote unit group that can be configured to determineprediction deviations among three remote units in the selected remoteunit group based on at least one RF signal;

FIG. 4 is a flowchart of an exemplary process of the control circuit ofFIG. 2 for optimizing RF coverage for reception at locations of theremote unit coverage areas in the WDS based on RF signal power levelsmeasured in selected remote unit coverage areas among the remote unitcoverage areas;

FIG. 5A is a schematic diagram providing an exemplary illustration ofthe at least one selected remote unit group of FIG. 3 for determiningone or more power correction factors based on a first power predictiondeviation and a second power prediction deviation;

FIG. 5B is a schematic diagram providing an exemplary illustration ofthe selected remote unit group of FIG. 3 for determining one or morepath loss correction factors based on a first power prediction deviationand a second power prediction deviation;

FIG. 6 is a schematic diagram of an exemplary selected remote unit groupincluding the three remote units of FIG. 3 and a fourth remote unit fordetermining correction factors with enhanced accuracy;

FIG. 7 is a schematic diagram of an exemplary selected remote unit groupconfigured to determine a correction factor for a selected correctionpoint located at a lower height than the three remote units in theselected remote unit group of FIG. 3;

FIG. 8 is a schematic diagram of an exemplary optical fiber-based WDSprovided in the form of an optical fiber-based DAS that includes the WDSof FIG. 2 configured to optimize RF coverage in the remote unit coverageareas;

FIG. 9 is a partial schematic cut-away diagram of an exemplary buildinginfrastructure in which the WDS of FIG. 2 can be provided; and

FIG. 10 is a schematic diagram representation of additional detailillustrating an exemplary computer system that could be employed in acontrol circuit(s) in the WDS of FIG. 2 for optimizing RF coverage inthe remote unit coverage areas.

DETAILED DESCRIPTION

Embodiments of the disclosure relate to optimizing radio frequency (RF)coverage in remote unit coverage areas in a wireless distribution system(WDS). Before a WDS is initially deployed, the placement design ofremote units in the WDS is based on predicted remote unit coverage areas(i.e., the transmission/reception coverage areas) from calculationsand/or simulations. However, the predicted remote unit coverage areasmay be different from actual remote unit coverage areas establishedafter deployment, because RF characteristics are difficult to factorinto the calculations and/or simulations due to potential signalobstruction elements (e.g., walls, floors, furniture, etc.). Hence, tooptimize RF coverage in the remote unit coverage areas after the WDS isdeployed, in certain aspects disclosed herein, a control circuit isprovided in the WDS and communicatively coupled to the remote unitsforming the remote unit coverage areas. The control circuit may beprovided in a central unit or located in one or more other components inthe WDS as examples. The control circuit is configured to selectivelydetermine at least one selected remote unit group including two or moreremote units selected from the remote units in the WDS. A remote unit inthe selected remote unit group is configured to transmit at least one RFsignal to the other remote units in the selected remote unit group todetermine prediction deviations (e.g., power prediction deviations)based on respective received RF signals. The control circuit isconfigured to determine one or more correction factors for one or moreselected correction points located within an area defined by theselected remote unit group based on the prediction deviations tooptimize RF coverage in the remote unit coverage areas serviced by theremote units in the selected remote unit group by correction factors.The correction factors can then be used to adjust one or more of theremote units to change the remote unit coverage areas with improvedaccuracy, thus improving RF performance and capacity of the WDS. Bydefining an appropriate number of selected remote unit groups involvingdifferent combinations of the remote units in the WDS, it is possible tooptimize RF coverage in all of the remote unit coverage areas in theWDS. As a result, overall RF performance and capacity of the WDS may beimproved.

In this regard, FIG. 2 is a schematic diagram of an exemplary WDS 200 inwhich a control circuit 202 is configured to optimize RF coverage in aplurality of remote unit coverage areas 204(1)-204(N) in the WDS 200based on actual RF signal power levels measured in selected remote unitcoverage areas among the remote unit coverage areas 204(1)-204(N). TheWDS 200 includes a plurality of remote units 206(1)-206(N) and a centralunit 208. In a non-limiting example, the control circuit 202 can beprovided in the central unit 208 as a centralized control circuit or oneor more of the remote units 206(1)-206(N) as a distributed controlcircuit. The control circuit 202 may also be hosted in other computingelements in the WDS 200. The remote units 206(1)-206(N) are configuredto receive a plurality of downlink communications signals 210(1)-210(N)from the central unit 208 over a plurality of downlink communicationsmediums 212(1)-212(N), and distribute the received downlinkcommunications signals 210(1)-210(N) to one or more client devices inthe remote unit coverage areas 204(1)-204(N), respectively. The remoteunits 206(1)-206(N) are also configured to receive a plurality of uplinkcommunications signals 214(1)-214(N) from the one or more client devicesin the remote unit coverage areas 204(1)-204(N). The remote units206(1)-206(N) are configured to provide the received uplinkcommunications signals 214(1)-214(N) to the central unit 208 over aplurality of uplink communications mediums 216(1)-216(N), respectively.In this regard, the remote units 206(1)-206(N) are configured to providedownlink and uplink communications services in the remote unit coverageareas 204(1)-204(N), respectively.

With continuing reference to FIG. 2, the remote unit coverage areas204(1)-204(N) may be organized into one or more cell areas218(1)-218(M). In a non-limiting example, the cell areas 218(1)-218(M)are defined based on communication services (e.g., long-term evolution(LTE)) and/or physical premises (e.g., buildings or floors withinbuildings). Each of the cell areas 218(1)-218(M) may include one or moreof the remote unit coverage areas 204(1)-204(N). For example, the cellarea 218(1) includes the remote unit coverage areas 204(1)-204(3), andthe cell area 218(M) includes the remote unit coverage areas204(N-3)-204(N).

In a non-limiting example, the remote unit coverage areas 204(1)-204(N)are determined based on intended coverage areas for a particulardeployment layout/design using simulation tools. The remote units206(1)-206(N) are deployed in the remote unit coverage areas204(1)-204(N) when the WDS 200 is initially deployed. Accordingly, theremote units 206(1)-206(N) are configured to transmit the downlinkcommunications signals 210(1)-210(N) in respective predictedtransmitting power levels to sufficiently cover the remote unit coverageareas 204(1)-204(N). In a non-limiting example, the respective predictedtransmitting power levels are determined to ensure client deviceslocated at a boundary of the remote unit coverage areas 204(1)-204(N)can receive the downlink communications signals 210(1)-210(N) withpredicted signal strengths. The remote units 206(1)-206(N) are alsoconfigured to receive the uplink communications signals 214(1)-214(N) inrespective predicted receiving power levels to provide adequatesignal-to-noise ratios (SNRs) in the received uplink communicationssignals 214(1)-214(N).

However, it may be difficult for the simulation tools to factor in RFcharacteristics of various signal obstruction elements (e.g., physicalobstructions and/or reflectors such as walls, floors, furniture, etc.)that may have a significant impact on propagations of the downlinkcommunications signals 210(1)-210(N) and/or the uplink communicationssignals 214(1)-214(N) in the remote unit coverage areas 204(1)-204(N).For example, propagations of the downlink communications signals210(1)-210(N) and or the uplink communications signals 214(1)-214(N) canbe impacted by the signal obstruction elements and their related RFcharacteristics (e.g., attenuation and/or reflection factors). In anon-limiting example, the signal obstruction elements can attenuate oneor more of the downlink communications signals 210(1)-210(N), thuscausing one or more of the remote unit coverage areas 204(1)-204(N) tobe reduced compared to predicted remote unit coverage areas determinedusing simulation tools. As a result, dead spots may be created in theremote unit coverage areas 204(1)-204(N), thus preventing client devicesfrom receiving the downlink communications signals 210(1)-210(N)correctly. In another non-limiting example, the signal obstructionelements can alter propagation path of the uplink communications signal214(1) transmitted by a client device in the remote unit coverage area204(1), thus causing the uplink communications signal 214(1) to bereceived by the remote unit 206(2) in the remote unit coverage area204(2) instead. Hence, it may be desirable to optimize RF coverage inthe remote unit coverage areas 204(1)-204(N) based on more accuratedetermination of the RF characteristics of the signal obstructionelements in the WDS 200.

In this regard, the control circuit 202, which is communicativelycoupled to the remote units 206(1)-206(N), is configured to determineprediction deviations based on at least one RF signal communicated in atleast one selected remote unit group 220. The selected remote unit group220 includes two or more remote units selected among the remote units206(1)-206(N) in the WDS 200. For the convenience of illustration andreference, the selected remote unit group 220 discussed hereinafterincludes three remote units that define a triangular-shaped coveragearea. It shall be appreciated that it is also possible to form theselected remote unit group 220 with two remote units or more than threeremote units. For example, the selected remote unit group 220 can beformed with four remote units, thus defining a quadrangular-shapedcoverage area, or with five remote units, thus defining apentagonal-shaped coverage area, and so on. As will be described in moredetail below, the control circuit 202 is further configured to optimizeRF coverage in the remote unit coverage areas 204(1)-204(N) serviced bythe three remote units in the selected remote unit group 220 based onthe determined prediction deviations. Specifically, an RF signaltransmitted by one of three remote units in the selected remote unitgroup 220 can be received at two other remote units in the selectedremote unit group 220. The RF signal actually received at the two otherremote units can be compared to the RF signal predicted to be receivedat the two other remote units to determine two prediction deviations atthe two other remote units. Accordingly, two correction factors may bedetermined for reception at locations of the two other remote units,respectively. The determined two correction factors can be usedsubsequently to determine a correction factor for a selected correctionpoint within an area defined by the three remote units. In anon-limiting example, the correction factor for the selected correctionpoint is proportional to linear distances between the selectedcorrection point and the three remote units in the selected remote unitgroup 220. As such, it is possible to adjust (e.g., increase ordecrease) the actual power level of the RF signal based on thedetermined correction factor for the selected correction point.

By determining the prediction deviations based on the RF signal(s)communicated in the selected remote unit group 220, it is possible forthe control circuit 202 to more accurately determine RF characteristicsof the signal obstruction elements in an area defined by the threeremote units in the selected remote unit group 220, thus optimizing RFcoverage in the remote unit coverage areas 204(1)-204(N) serviced by thethree remote units in the selected remote unit group 220. Accordingly,by defining an appropriate number of selected remote unit groupsinvolving different combinations of the remote units 206(1)-206(N), itis possible to determine prediction deviations in these selected remoteunit groups, thus optimizing RF coverage in all of the remote unitcoverage areas 204(1)-204(N) in the WDS 200. As a result, overall RFperformance and capacity of the WDS 200 may be improved.

For the convenience of illustration and discussion, the selected remoteunit group 220 as shown therein includes the remote unit 206(1), theremote unit 206(2), and the remote unit 206(3). It shall be appreciatedthat the selected remote unit group 220 can be defined based on any ofthe remote units 206(1)-206(N) in the WDS 200. For example, the selectedremote unit group 220 can be constructed to include the remote unit206(1), the remote unit 206(N-3), and the remote unit 206(N), or anyother remote unit combination as appropriate. In addition, it ispossible for any of the remote units 206(1)-206(N) to be included inmore than one selected remote unit group. It shall be furtherappreciated that the mechanisms for optimizing RF coverage in the remoteunit coverage areas 204(1)-204(3) discussed with reference to theselected remote unit group 220 can be used to optimize RF coverage inany of the remote unit coverage areas 204(1)-204(N) in the WDS 200.

In this regard, FIG. 3 is a schematic diagram providing an exemplaryillustration of the selected remote unit group 220 of FIG. 2 that can beconfigured to determine prediction deviations among the three remoteunits 206(1)-206(3) in this example based on at least one RF signal 300.Common elements between FIGS. 2 and 3 are shown therein with commonelement numbers and will not be re-described herein. As discussed above,an RF signal transmitted by one of three remote units in the selectedremote unit group 220 can be received at two other remote units in theselected remote unit group 220. The RF signal actually received at thetwo other remote units can be compared to the RF signal predicted to bereceived at the two other remote units to determine two predictiondeviations at the locations of the two other remote units. Accordingly,two correction factors may be determined for the locations of the twoother remote units, respectively. The determined two correction factorscan be used subsequently to determine a correction factor for a selectedcorrection point within an area defined by the three remote units. In anon-limiting example, the correction factor for the selected correctionpoint is proportional to linear distances between the selectedcorrection point and the three remote units in the selected remote unitgroup 220. As such, it is possible to adjust (e.g., increase ordecrease) the actual power level of the RF signal based on thedetermined correction factor for the selected correction point.

In one embodiment, power level of the RF signal transmitted by one ofthe three remote units in the selected remote unit group 220 can bemeasured at the two other remote units in the selected remote unit group220. The two measured actual power levels can be compared to twopredicted power levels for the two other remote units to determine twopower prediction deviations at the locations of the two other remoteunits. Accordingly, two power correction factors may be determined forthe locations of the two other remote units, respectively. Thedetermined two power correction factors can be used subsequently todetermine a power correction factor for a selected correction pointwithin an area defined by the three remote units. In this regard, withreference to FIG. 3, in a non-limiting example, the remote units206(1)-206(3) in the selected remote unit group 220 are designated as afirst remote unit 302 (also referenced as point A), a second remote unit304 (also referenced as point B), and a third remote unit 306 (alsoreferenced as point C), respectively. The control circuit 202 iscommunicatively coupled to the first remote unit 302, the second remoteunit 304, and the third remote unit 306. It shall be appreciated thatany of the remote units 206(1)-206(3) can be designated as the firstremote unit 302 without adversely impacting determination of theprediction deviations in the selected remote unit group 220.

The first remote unit 302, the second remote unit 304, and the thirdremote unit 306 define an area 308. In a non-limiting example, the area308 is a triangular-shaped area defined by point A, point B, and pointC. The control circuit 202 is configured to instruct the first remoteunit 302 in the selected remote unit group 220 to transmit the RF signal300 at a first actual power level P₁. In response to receivinginstructions from the control circuit 202, the first remote unit 302 isconfigured to transmit the RF signal 300 to the second remote unit 304and the third remote unit 306 in the selected remote unit group 220concurrently. As the RF signal 300 propagates through the area 308, oneor more signal obstruction elements may cause the first actual powerlevel P₁ of the RF signal 300 to change when the RF signal 300 arrivesat the second remote unit 304 and the third remote unit 306. In thisregard, the second remote unit 304 may receive the RF signal 300 at asecond actual power level P₂, and the third remote unit 306 may receivethe RF signal 300 at a third actual power level P₃. In the meantime, thesecond remote unit 304 and the third remote unit 306 may have beenpreviously predicted by the simulation tools prior to deployment toreceive the RF signal 300 at a first predicted receiving power level Pp₁and a second predicted receiving power level Pp₂, respectively. As such,RF signal obstruction elements may be causing the second actual powerlevel P₂ at the second remote unit 304 to be different from the firstpredicted receiving power level Pp₁ at the second remote unit 304.Likewise, RF signal obstruction elements may be causing the third actualpower level P₃ the third remote unit 306 to be different from the secondpredicted receiving power level Pp₂ at the third remote unit 306. Thecontrol circuit 202 is aware of the first predicted receiving powerlevel Pp₁ at the second remote unit 304 and the second predictedreceiving power level Pp₂ at the third remote unit 306. In anon-limiting example, the control circuit 202 stores the first predictedreceiving power level Pp₁ and the second predicted receiving power levelPp₂ in a storage media.

In this regard, the control circuit 202 instructs the second remote unit304 to receive the RF signal 300 at the second actual power level P₂. Ina non-limiting example, the second remote unit 304 communicates thesecond actual power level P₂ to the control circuit 202. Subsequently,the control circuit 202 determines a first power prediction deviationΔ_(@B) at the second remote unit 304 by subtracting the first predictedreceiving power level Pp₁ from the second actual power level P₂.According to previous discussions in FIG. 2, the control circuit 202 maybe provided in the second remote unit 304. As such, it shall beappreciated that it is possible for the second remote unit 304 todetermine the first power prediction deviation Δ_(@B) as well. Thecontrol circuit 202 also instructs the third remote unit 306 to receivethe RF signal 300 at the third actual power level P₃. In a non-limitingexample, the third remote unit 306 communicates the third actual powerlevel P₃ to the control circuit 202. Subsequently, the control circuit202 determines a second power prediction deviation Δ_(@C) at the thirdremote unit 306 by subtracting the second predicted receiving powerlevel Pp₂ from the third actual power level P₃. According to previousdiscussions in FIG. 2, the control circuit 202 may be provided in thethird remote unit 306. As such, it shall be appreciated that it ispossible for the third remote unit 306 to determine the second powerprediction deviation Δ_(@C) as well.

With continuing reference to FIG. 3, the control circuit 202 is thenfurther configured to determine one or more correction factorsΔ_(@1)-Δ_(@L) for one or more selected correction points 310(1)-310(L)located in the area 308, respectively, based on the power predictiondeviations A_(@B) and Δ_(@C). In a non-limiting example, the selectedcorrection point 310(1) (also referenced as point M) is located on afirst straight line 312 connecting points B and C. As is furtherdiscussed later, the correction factors Δ_(@1)-Δ_(@L) can be eitherpower correction factors or path loss correction factors. In the samenon-limiting example, the selected correction point 310(L) (alsoreferenced as point N) is located on a second straight line 314connecting points A and M. The control circuit 202 is configured todetermine the correction factor Δ_(@1) for the selected correction point310(1) based on the equation (Eq. 1) below.Δ_(@1)=(d _(BM) /d _(BC))×(Δ_(@C)−Δ_(@B))+Δ_(@B)  (Eq. 1)

With reference to Eq. 1, d_(BM) refers to a linear distance from point Bto point M, and d_(BC) refers to a linear distance from point B to pointC. In this regard, the control circuit 202 can determine a respectivecorrection factor for any correction point located on the first straightline 312 based on Eq. 1. The control circuit 202 is configured todetermine the correction factor Δ_(@L) based on the equation (Eq. 2)below.Δ_(@L)=(d _(AN) /d _(AM))×Δ_(@1)  (Eq. 2)

With reference to Eq. 2, d_(AN) refers to a linear distance from point Ato point N and d_(AM) refers to a linear distance from point A to pointM. In this regard, the control circuit 202 can determine correctionfactors Δ_(@2)-Δ_(@L) for the selected correction points 310(2)-310(L)located on the second straight line 314 based on Eq. 2. Thus, thecontrol circuit 202 can determine a respective correction factor for anycorrection point located within the area 308 based on Eq. 1 and Eq. 2.For example, by moving the selected correction point 310(1) (point M) toa selected correction point 310′(1) (point M′) along the first straightline 312, the control circuit 202 can determine a correction factorΔ′_(@1) for the selected correction point 310′(1) based on Eq. 1.Further, the control circuit 202 can determine correction factorsΔ′_(@2)-Δ′_(@L) for the selected correction points 310′(2)-310′(L)located on a third straight line 316 connecting the points A and M′based on Eq. 2.

With reference back to FIG. 2, the control circuit 202 can be configuredto optimize RF coverage in the remote unit coverage areas 204(1)-204(N)according to a process. In this regard, FIG. 4 is a flowchart of anexemplary process 400 of the control circuit 202 of FIG. 2 foroptimizing RF coverage for reception at locations of the remote unitcoverage areas 204(1)-204(N) in the WDS 200;

With reference to FIG. 4, the control circuit 202 determines theselected remote unit group 220 including the remote units 206(1)-206(3)among the remote units 206(1)-206(N) in the WDS 200 (block 402). Thecontrol circuit 202 instructs the first remote unit 302 in the selectedremote unit group 220 to transmit the RF signal 300 (block 404). Thecontrol circuit 202 instructs the second remote unit 304 in the selectedremote unit group 220 to receive the RF signal 300 (block 406). Thecontrol circuit 202 determines the first power prediction deviationΔ_(@B) at the second remote unit 304 based on the difference between theRF signal 300 received at the second remote unit 304 and the RF signal300 predicted to be received at the second remote unit 304 (block 408).The control circuit 202 instructs the third remote unit 306 in theselected remote unit group 220 to receive the RF signal 300 (block 410).The control circuit 202 determines the second power prediction deviationΔ_(@C) at the third remote unit 306 based on the difference between theRF signal 300 received at the third remote unit 306 and the RF signal300 predicted to be received at the third remote unit 306 (block 412).The control circuit 202 determines the correction factors Δ_(@1)-Δ_(@L)for the selected correction points 310(1)-310(L) located within the area308 defined by the selected remote unit group 220 based on the firstpower prediction deviation Δ_(@B) and the second power predictiondeviation Δ_(@C) (block 414).

With reference back to FIG. 3, in a first non-limiting example, thecorrection factors Δ_(@1)-Δ_(@L) may be one or more power correctionfactors ΔP_(@1)-ΔP_(@L) for the selected correction points310(1)-310(L). In this regard, FIG. 5A is a schematic diagram providingan exemplary illustration of the selected remote unit group 220 of FIG.3 for determining the power correction factors ΔP_(@1)-ΔP_(@L) based onthe first power prediction deviation Δ_(@B) and the second powerprediction deviation Δ_(@C). Common elements between FIGS. 2, 3, and 5Aare shown therein with common element numbers and will not bere-described herein.

With reference to FIG. 5A, the control circuit 202 is configured todetermine the power correction factors ΔP_(@1)-ΔP_(@L) based on thefirst power prediction deviation Δ_(@B) and the second power predictiondeviation Δ_(@C). The control circuit 202 is configured to determine thepower correction factor ΔP_(@1) for the selected correction point 310(1)based on the equation (Eq. 3) below.ΔP _(@1)=(d _(BM) /d _(BC))×(Δ_(@C)−Δ_(@B))Δ_(@B)  (Eq. 3)

With reference to Eq. 3, d_(BM) refers to the linear distance from pointB to point M, and d_(BC) refers to the linear distance from point B topoint C. In this regard, the control circuit 202 can determine therespective power correction factor for any correction point located onthe first straight line 312 based on Eq. 3. The control circuit 202 isconfigured to determine the power correction factor ΔP_(@L) based on theequation (Eq. 4) below.ΔP _(@L)=(d _(AN) /d _(AM))×ΔP _(@1)  (Eq. 4)

With reference to Eq. 4, d_(AN) refers to the linear distance from pointA to point N, and d_(AM) refers to the linear distance from point A topoint M. In this regard, the control circuit 202 can determine the powercorrection factors ΔP_(@2)-ΔP_(@L) for the selected correction points310(2)-310(L) located on the second straight line 314 based on Eq. 4.Thus, the control circuit 202 can determine the respective powercorrection factor for any correction point located within the area 308based on Eq. 3 and Eq. 4.

Based on the determined power correction factors ΔP_(@1)-ΔP_(@L), thecontrol circuit 202 is able to determine whether actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are higherthan, lower than, or equal to predicted power levels P_(P@1)-P_(P@L) atthe selected correction points 310(1)-310(L). In a non-limiting example,the control circuit 202 can determine that the actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are higherthan the predicted power levels P_(P@1)-P_(P@L) when the powercorrection factors Δ_(P@1)-A_(P@L) are greater than zero (0). Likewise,the control circuit 202 can determine that the actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are lowerthan the predicted power levels P_(P@1)-P_(P@L) when the powercorrection factors Δ_(P@1)-Δ_(P@L) are less than 0. Similarly, thecontrol circuit 202 can determine that the actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are equalto the predicted power levels P_(P@1)-P_(P@L) when the power correctionfactors Δ_(P@1)-Δ_(P@L) are equal to 0. Further, the control circuit 202may determine that some of the actual power levels P_(@1)-P_(@L) at theselected correction points 310(1)-310(L) are higher than the predictedpower levels P_(P@1)-P_(P@L), some of the actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are lowerthan the predicted power levels P_(P@1)-P_(P@L), and some of the actualpower levels P_(@1)-P_(@L) at the selected correction points310(1)-310(L) are equal to the predicted power levels P_(P@1)-P_(P@L).Accordingly, the control circuit 202 can control the first remote unit302 to decrease, increase, or maintain the first power level P₁ of theRF signal 300 in response to determining that the actual power levelsP_(@1)-P_(@L) at the selected correction points 310(1)-310(L) are higherthan, lower than, or equal to the predicted power levels P_(P@1)-P_(P@L)at the selected correction points 310(1)-310(L).

With reference back to FIG. 3, in a second non-limiting example, thecorrection factors Δ_(@1)-Δ_(@L), may be one or more path losscorrection factors ΔPL_(@1)-ΔPL_(@L) for the selected correction points310(1)-310(L). In this regard, FIG. 5B is a schematic diagram providingan exemplary illustration of the selected remote unit group 220 of FIG.3 for determining the path loss correction factors ΔPL_(@1)-ΔPL_(@L)based on the first power prediction deviation Δ_(@B) and the secondpower prediction deviation Δ_(@C). Common elements between FIGS. 2, 3,and 5B are shown therein with common element numbers and will not bere-described herein.

With reference to FIG. 5B, the control circuit 202 is configured todetermine a first actual path loss PL₁ at the second remote unit 304based on the second actual power level P₂ and the first actual powerlevel P₁ of the RF signal 300. The control circuit 202 is furtherconfigured to determine a first path loss prediction deviation ΔPL_(@B)based on a difference between the first actual path loss PL₁ and a firstpredicted path loss PL_(P1) at the second remote unit 304. Similarly,the control circuit 202 is configured to determine a second actual pathloss PL₂ at the third remote unit 306 based on a difference between thethird actual power level P₃ and the first actual power P₁ of the RFsignal 300. The control circuit 202 is further configured to determine asecond path loss prediction deviation ΔPL_(@C) based on the determinedsecond actual path loss PL₂ and a second predicted path loss PL_(P2) atthe third remote unit 306. The control circuit 202 is configured todetermine the path loss correction factor ΔPL_(@1) for the selectedcorrection point 310(1) based on the equation (Eq. 5) below.ΔPL _(@1)=(d _(BM) /d _(BC))×(ΔPL _(@C) −ΔPL _(@B))+ΔPL _(@B)  (Eq. 5)

With reference to Eq. 5, d_(BM) refers to the linear distance from pointB to point M, and d_(BC) refers to the linear distance from point B topoint C. In this regard, the control circuit 202 can determine therespective path loss correction factor for any correction point locatedon the first straight line 312 based on Eq. 5. The control circuit 202is configured to determine the path loss correction factors ΔP_(@L)based on the equation (Eq. 6) below.ΔPL _(@L)=(d _(AN) /d _(AM))×ΔPL _(@1)  (Eq. 6)

With reference to Eq. 6, d_(AN) refers to the linear distance from pointA to point N, and d_(AM) refers to the linear distance from point A topoint M. In this regard, the control circuit 202 can determine the pathloss correction factors ΔPL_(@2)-ΔPL_(@L) for the selected correctionpoints 310(2)-310(L) located on the second straight line 314 based onEq. 6. Thus, the control circuit 202 can determine the respective pathloss correction factor for any correction point located within the area308 based on Eq. 5 and Eq. 6.

Based on the path loss correction factors ΔPL_(@1)-ΔPL_(@L), the controlcircuit 202 is able to determine whether actual path lossesPL_(@1)-PL_(@L) at the selected correction points 310(1)-310(L) arehigher than, lower than, or equal to predicted path lossesPL_(P@1)-PL_(P@L) at the selected correction points 310(1)-310(L). In anon-limiting example, the control circuit 202 can determine that theactual path losses PL_(@1)-PL_(@L) at the selected correction points310(1)-310(L) are higher than the predicted path lossesPL_(P@1)-PL_(P@L) when the path loss correction factorsΔPL_(@1)-ΔPL_(@L) are greater than zero (0). Likewise, the controlcircuit 202 can determine that the actual path losses PL_(@1)-PL_(@L) atthe selected correction points 310(1)-310(L) are lower than thepredicted path losses PL_(P@1)-PL_(P@L) when the path loss correctionfactors ΔPL_(@1)-ΔPL_(@L) are less than 0. Similarly, the controlcircuit 202 can determine that the actual path losses PL_(@1)-PL_(@L) atthe selected correction points 310(1)-310(L) are equal to the predictedpath losses PL_(P@1)-PL_(P@L) when the path loss correction factorsΔPL_(@1)-ΔPL_(@L) are equal to 0. Accordingly, the control circuit 202can control the first remote unit 302 to increase, decrease, or maintainthe first actual power level P₁ of the RF signal 300 in response todetermining that the actual path losses PL_(@1)-PL_(@L) at the selectedcorrection points 310(1)-310(L) are respectively higher than, lowerthan, or equal to the predicted path losses PL_(P@1)-PL_(P@L) at theselected correction points 310(1)-310(L).

With reference back to FIG. 3, in a non-limiting example, the firstremote unit 302 in the selected remote unit group 220 is configured totransmit the RF signal 300 that includes at least one non-modulatedcontinuous wave signal. The non-modulated continuous wave signal canhelp improve receiver sensitivity at the second remote unit 304 and thethird remote unit 306 in the selected remote unit group 220.Accordingly, RF receivers at the second remote unit 304 and the thirdremote unit 306 are configured to receive the non-modulated continuouswave signal at a defined RF filter bandwidth, which can be one kilohertz(1 KHz), for example.

With continuing reference to FIG. 3, in a first non-limiting example,the RF signal 300 transmitted by the first remote unit 302 is in adownlink frequency range of at least one of the second remote unit 304and the third remote unit 306 in the selected remote unit group 220. Inthis regard, the control circuit 202 instructs the at least one of thesecond remote unit 304 and the third remote unit 306 to receive the RFsignal 300 in a listening mode in the downlink frequency range. In asecond non-limiting example, the RF signal 300 transmitted by the firstremote unit 302 is in an uplink frequency range of at least one of thesecond remote unit 304 and the third remote unit 306 in the selectedremote unit group 220. In this regard, the control circuit 202 furtherinstructs the at least one of the second remote unit 304 and the thirdremote unit 306 to receive the RF signal 300 in the listening mode inthe uplink frequency range.

In another non-limiting example, the first remote unit 302 in theselected remote unit group 220 is configured to transmit the RF signal330 that includes a plurality of non-coherent frequencies correspondingto a plurality of assigned weight factors, respectively. Thenon-coherent frequencies, which provide frequency diversity, can helpneutralize selective fading effects that are typically frequencydependent. In this regard, the second remote unit 304 in the selectedremote unit group 220 is configured to receive the RF signal 300 in thenon-coherent frequencies. The second remote unit 304 is furtherconfigured to determine the first power prediction deviation Δ_(@B)based on the assigned weight factors corresponding to the non-coherentfrequencies. Likewise, the third remote unit 306 in the selected remoteunit group 220 is configured to receive the RF signal 300 in thenon-coherent frequencies. The third remote unit 306 is furtherconfigured to determine the second power prediction deviation Δ_(@C)based on the assigned weight factors corresponding to the non-coherentfrequencies.

According to Eq. 2, the control circuit 202 determines the correctionfactor Δ_(@L) in the selected remote unit group 220 based on thecorrection factor Δ_(@1), which is further determined based on Eq. 1. Ina non-limiting example, it is possible to enhance and/or verify accuracyof the correction factor Δ_(@L) determined based on Eq. 2 by determiningmultiple versions of the correction factor Δ_(@L). In this regard, FIG.6 is a schematic diagram of an exemplary second selected remote unitgroup 600 including the first remote unit 302 of FIG. 3, the secondremote unit 304 of FIG. 3, the third remote unit 306 of FIG. 3, and afourth remote unit 602 for determining at least one correction factorΔ_(@N) with enhanced accuracy. Common elements between FIGS. 3 and 6 areshown therein with common element numbers and will not be re-describedherein.

With reference to FIG. 6, the control circuit 202 instructs the firstremote unit 302 to transmit the RF signal 300 at the first actual powerlevel P₁. The control circuit 202 instructs the second remote unit 304to receive the RF signal 300 at the second actual power level P₂. Thecontrol circuit 202 determines the first power prediction deviationΔ_(@B) at the second remote unit 304 based on the difference between thereceived second actual power level P₂ and the first predicted receivingpower level P_(P1).

The control circuit 202 instructs the third remote unit 306 to receivethe RF signal 300 at the third actual power level P₃. The controlcircuit 202 determines the second power prediction deviation Δ_(@C) atthe third remote unit 306 based on the difference between the receivedthird actual power level P₃ and the second predicted receiving powerlevel P_(P2).

With continuing reference to FIG. 6, the control circuit 202 instructsthe fourth remote unit 602 (also referenced as point D) to transmit atleast one second RF signal 604 at a fourth actual power level P₄. Thecontrol circuit 202 instructs the second remote unit 304 to receive thesecond RF signal 604 at a fifth actual power level P₅. The controlcircuit 202 determines a third power prediction deviation Δ_(@BB) basedon the difference between the received fifth actual power level P₅ andthe first predicted receiving power level P_(P1).

The control circuit 202 instructs the third remote unit 306 to receivethe second RF signal 604 at a sixth actual power level P₆. The controlcircuit 202 determines a fourth power prediction deviation Δ_(@CC) basedon the difference between the received sixth actual power level P₆ andthe second predicted receiving power level P_(P2).

Accordingly, the control circuit 202 determines the at least onecorrection factor Δ_(@N) among the correction factors Δ_(@1)-Δ_(@L) ofFIG. 3 based on the first power prediction deviation Δ_(@B), the secondpower prediction deviation Δ_(@C), the third power prediction deviationΔ_(@BB), and the fourth power prediction deviation Δ_(@CC).Specifically, the control circuit 202 first determines a firstcorrection factor Δ_(@M1) based on the equation (Eq. 7) below.Δ_(@M1)=(d _(BM1) /d _(BC))×(A _(@C)−Δ_(@B))+Δ_(@B)  (Eq. 7)

With reference to Eq. 7, d_(BM1) refers to a linear distance from pointB to point M1, and d_(BC) refers to the linear distance from point B topoint C. The control circuit 202 is configured to determine a firstreference correction factor Δ_(@N1) based on the equation (Eq. 8) below.Δ_(@N1)=(d _(AN) /d _(AM1))×Δ_(@M1)  (Eq. 8)

With reference to Eq. 8, d_(AN) refers to the linear distance from pointA to point N, and d_(AM1) refers to a linear distance from point A topoint M1. Next, the control circuit 202 determines a second correctionfactor Δ_(@M2) based on the equation (Eq. 9) below.Δ_(@M2)=(d _(CM2) /d _(CB))×(A _(@BB)−Δ_(@CC))+Δ_(@CC)  (Eq. 9)

With reference to Eq. 9, d_(CM2) refers to a linear distance from pointC to point M2, and d_(C3) refers to a linear distance from point C topoint B. The control circuit 202 is configured to determine a secondreference correction factor Δ_(@N2) based on the equation (Eq. 10)below.Δ_(@N2)=(d _(DN) /d _(DM2))×Δ_(@M2)  (Eq. 10)

With reference to Eq. 10, d_(DN) refers to a linear distance from pointD to point N and d_(DM2) refers to a linear distance from point D topoint M2. As such, the control circuit 202 can determine the correctionfactor Δ_(@N) based on the first reference correction factor Δ_(@N1) andthe second reference correction factor Δ_(@N2), thus improving accuracyof the correction factor Δ_(@N). In a non-limiting example, the controlcircuit 202 can determine the correction factor Δ_(@N) by averaging thefirst and section reference correction factors Δ_(@N1) and Δ_(@N2).

With reference back to FIG. 3, in a non-limiting example, the firstremote unit 302, the second remote unit 304, and the third remote unit306 are mounted on a same ceiling of a building. In this regard, thefirst remote unit 302, the second remote unit 304, and the third remoteunit 306 in the selected remote unit group 220 are located at a firstheight from a ground level (e.g., a floor in the building). In thisregard, according to the same non-limiting example, the selectedcorrection points 310(1)-310(L) are also located approximately at thefirst height from the ground level.

However, it may be possible that a selected correction point (e.g., aclient device) among the selected correction points 310(1)-310(L) islocated at a second height from the ground level, and the second heightis lower than the first height. In this regard, FIG. 7 is a schematicdiagram of an exemplary selected remote unit group 700 configured todetermine a correction factor Δ_(@N1) for a selected correction point N1located at a lower height than the first remote unit 302, the secondremote unit 304, and the third remote unit 306 in the selected remoteunit group 220 of FIG. 3. Common elements between FIGS. 3 and 6 areshown therein with common element numbers and will not be re-describedherein.

With reference to FIG. 7, the first remote unit 302, the second remoteunit 304, and the third remote unit 306 are located at a first height H₁from a ground level 702. However, the selected correction point N1 islocated at a second height H₂ from the ground level 702, and the secondheight H₂ is lower than the first height H₁. In a non-limiting example,the selected correction point N1 is a client device held by a user. Theselected correction point N1 has a predicted power level P_(P@N1), whichis generated via calculation and/or simulation. To determine acorrection factor Δ_(@N1), the control circuit 202 is configured tofirst determine the correction factor Δ_(@M) based on Eq. 1 discussedabove. Next, the control circuit 202 is configured to determine acorrection factor Δ_(@N) based on Eq. 2 discussed above. The controlcircuit 202 is further configured to determine the correction factorΔ_(@N1) for the selected correction point N1 based on the equation (Eq.11) below. As such, the correction factor Δ_(@N1) can be used to improveRF performance for client devices located within the area 308.Δ_(@N1) =P _(P@N1)−Δ_(@N)  (Eq. 11)

With reference back to FIG. 2, the central unit 208 is communicativelycoupled to one or more signal sources 222(1)-222(K). In a non-limitingexample, the signal sources 222(1)-222(K) are digital baseband units(BBUs) and/or base transceiver stations (BTSs). The signal sources222(1)-222(K) are configured to communicate with the central unit 208based on communication protocols, such as common public radio interface(CPRI), open base station architecture initiative (OBSAI) protocol, openradio equipment interface (ORI) protocol, or proprietary communicationprotocols.

FIG. 8 is a schematic diagram of an exemplary optical fiber-based WDS800 provided in the form of an optical fiber-based DAS that includes theWDS 200 of FIG. 2 configured to optimize RF coverage in the remote unitcoverage areas 204(1)-204(N). The WDS 800 includes an optical fiber fordistributing communications services for multiple frequency bands. TheWDS 800 in this example is comprised of three main components. One ormore radio interfaces provided in the form of radio interface modules(RIMS) 802(1)-802(M) are provided in a central unit 804 to receive andprocess downlink electrical communications signals 806D(1)-806D(R) priorto optical conversion into downlink optical fiber-based communicationssignals. The downlink electrical communications signals 806D(1)-806D(R)may be received from a base station as an example. The RIMs802(1)-802(M) provide both downlink and uplink interfaces for signalprocessing. The notations “1-R” and “1-M” indicate that any number ofthe referenced component, 1-R and 1-M, respectively, may be provided.The central unit 804 is configured to accept the RIMs 802(1)-802(M) asmodular components that can easily be installed and removed or replacedin the central unit 804. In one example, the central unit 804 isconfigured to support up to twelve RIMs 802(1)-802(12). Each RIM802(1)-802(M) can be designed to support a particular type of radiosource or range of radio sources (i.e., frequencies) to provideflexibility in configuring the central unit 804 and the WDS 800 tosupport the desired radio sources.

For example, one RIM 802 may be configured to support the PCS radioband. Another RIM 802 may be configured to support the 800 megahertz(MHz) radio band. In this example, by inclusion of these RIMs 802, thecentral unit 804 could be configured to support and distributecommunications signals on both PCS and LTE 700 radio bands, as anexample. The RIMs 802 may be provided in the central unit 804 thatsupport any frequency bands desired, including but not limited to the USCellular band, PCS band, AWS band, 700 MHz band, Global System forMobile communications (GSM) 900, GSM 1800, and Universal MobileTelecommunications System (UMTS). The RIMs 802(1)-802(M) may also beprovided in the central unit 804 that support any wireless technologiesdesired, including but not limited to Code Division Multiple Access(CDMA), CDMA200, 1×RTT, Evolution-Data Only (EV-DO), UMTS, High-speedPacket Access (HSPA), GSM, General Packet Radio Services (GPRS),Enhanced Data GSM Environment (EDGE), Time Division Multiple Access(TDMA), LTE, iDEN, and Cellular Digital Packet Data (CDPD).

The RIMs 802(1)-802(M) may be provided in the central unit 804 thatsupport any frequencies desired, including but not limited to US FCC andIndustry Canada frequencies (824-849 MHz on uplink and 869-894 MHz ondownlink), US FCC and Industry Canada frequencies (1850-1915 MHz onuplink and 1930-1995 MHz on downlink), US FCC and Industry Canadafrequencies (1710-1755 MHz on uplink and 2110-2155 MHz on downlink), USFCC frequencies (698-716 MHz and 776-787 MHz on uplink and 728-746 MHzon downlink), EU R & TTE frequencies (880-915 MHz on uplink and 925-960MHz on downlink), EU R & TTE frequencies (1710-1785 MHz on uplink and1805-1880 MHz on downlink), EU R & TTE frequencies (1920-1980 MHz onuplink and 2110-2170 MHz on downlink), US FCC frequencies (806-824 MHzon uplink and 851-869 MHz on downlink), US FCC frequencies (896-901 MHzon uplink and 929-941 MHz on downlink), US FCC frequencies (793-805 MHzon uplink and 763-775 MHz on downlink), and US FCC frequencies(2495-2690 MHz on uplink and downlink).

With continuing reference to FIG. 8, the downlink electricalcommunications signals 806D(1)-806D(R) are provided to a plurality ofoptical interfaces provided in the form of optical interface modules(OIMs) 808(1)-808(N) in this embodiment to convert the downlinkelectrical communications signals 806D(1)-806D(R) into downlink opticalfiber-based communications signals 810D(1)-810D(R). The notation “1-N”indicates that any number of the referenced component 1-N may beprovided. The OIMs 808(1)-808(N) may be configured to provide one ormore optical interface components (OICs) that containoptical-to-electrical (O/E) and electrical-to-optical (E/O) converters,as will be described in more detail below. The OIMs 808(1)-808(N)support the radio bands that can be provided by the RIMs 802(1)-802(M),including the examples previously described above.

The OIMs 808(1)-808(N) each include E/O converters to convert thedownlink electrical communications signals 806D(1)-806D(R) into thedownlink optical fiber-based communications signals 810D(1)-810D(R). Thedownlink optical fiber-based communications signals 810D(1)-810D(R) arecommunicated over a downlink optical fiber-based communications medium812D to a plurality of remote antenna units (RAUs) 814(1)-814(S). Thenotation “1-S” indicates that any number of the referenced component 1-Smay be provided. O/E converters provided in the RAUs 814(1)-814(S)convert the downlink optical fiber-based communications signals810D(1)-810D(R) back into the downlink electrical communications signals806D(1)-806D(R), which are provided to antennas 816(1)-816(S) in theRAUs 814(1)-814(S) to client devices in the reception range of theantennas 816(1)-816(S).

E/O converters are also provided in the RAUs 814(1)-814(S) to convertuplink electrical communications signals 818U(1)-818U(S) received fromclient devices through the antennas 816(1)-816(S) into uplink opticalfiber-based communications signals 810U(1)-810U(S). The RAUs814(1)-814(S) communicate the uplink optical fiber-based communicationssignals 810U(1)-810U(S) over an uplink optical fiber-basedcommunications medium 812U to the OIMs 808(1)-808(N) in the central unit804. The OIMs 808(1)-808(N) include O/E converters that convert thereceived uplink optical fiber-based communications signals810U(1)-810U(S) into uplink electrical communications signals820U(1)-820U(S), which are processed by the RIMS 802(1)-802(M) andprovided as uplink electrical communications signals 820U(1)-820U(S).The central unit 804 may provide the uplink electrical communicationssignals 820U(1)-820U(S) to a base station or other communicationssystem.

Note that the downlink optical fiber-based communications medium 812Dand the uplink optical fiber-based communications medium 812U connectedto each RAU 814(1)-814(S) may be a common optical fiber-basedcommunications medium, wherein for example, wave division multiplexing(WDM) is employed to provide the downlink optical fiber-basedcommunications signals 810D(1)-810D(R) and the uplink opticalfiber-based communications signals 810U(1)-810U(S) on the same opticalfiber-based communications medium.

The WDS 200 of FIG. 2 may be provided in an indoor environment, asillustrated in FIG. 9. FIG. 9 is a partial schematic cut-away diagram ofan exemplary building infrastructure 900 in which the WDS 200 of FIG. 2can be employed. The building infrastructure 900 in this embodimentincludes a first (ground) floor 902(1), a second floor 902(2), and athird floor 902(3). The floors 902(1)-902(3) are serviced by a centralunit 904 to provide antenna coverage areas 906 in the buildinginfrastructure 900. The central unit 904 is communicatively coupled to abase station 908 to receive downlink communications signals 910D fromthe base station 908. The central unit 904 is communicatively coupled toa plurality of remote units 912 to distribute the downlinkcommunications signals 910D to the remote units 912 and to receiveuplink communications signals 910U from the remote units 912, aspreviously discussed above. The downlink communications signals 910D andthe uplink communications signals 910U communicated between the centralunit 904, and the remote units 912 are carried over a riser cable 914.The riser cable 914 may be routed through interconnect units (ICUs)916(1)-916(3) dedicated to each of the floors 902(1)-902(3) that routethe downlink communications signals 910D and the uplink communicationssignals 910U to the remote units 912 and also provide power to theremote units 912 via array cables 918.

FIG. 10 is a schematic diagram representation of additional detailillustrating an exemplary computer system 1000 that could be employed ina control circuit, including the control circuit 202 of FIG. 2, foroptimizing RF coverage in the remote unit coverage areas 204(1)-204(N)in the WDS 200 of FIG. 2. In this regard, the computer system 1000 isadapted to execute instructions from an exemplary computer-readablemedium to perform these and/or any of the functions or processingdescribed herein.

In this regard, the computer system 1000 in FIG. 10 may include a set ofinstructions that may be executed to predict frequency interference toavoid or reduce interference in a multi-frequency DAS. The computersystem 1000 may be connected (e.g., networked) to other machines in aLAN, an intranet, an extranet, or the Internet. While only a singledevice is illustrated, the term “device” shall also be taken to includeany collection of devices that individually or jointly execute a set (ormultiple sets) of instructions to perform any one or more of themethodologies discussed herein. The computer system 1000 may be acircuit or circuits included in an electronic board card, such as aprinted circuit board (PCB), a server, a personal computer, a desktopcomputer, a laptop computer, a personal digital assistant (PDA), acomputing pad, a mobile device, or any other device, and may represent,for example, a server or a user's computer.

The exemplary computer system 1000 in this embodiment includes aprocessing device or processor 1002, a main memory 1004 (e.g., read-onlymemory (ROM), flash memory, dynamic random access memory (DRAM), such assynchronous DRAM (SDRAM), etc.), and a static memory 1006 (e.g., flashmemory, static random access memory (SRAM), etc.), which may communicatewith each other via a data bus 1008. Alternatively, the processor 1002may be connected to the main memory 1004 and/or the static memory 1006directly or via some other connectivity means. The processor 1002 may bea controller, and the main memory 1004 or the static memory 1006 may beany type of memory.

The processor 1002 represents one or more general-purpose processingdevices, such as a microprocessor, central processing unit, or the like.More particularly, the processor 1002 may be a complex instruction setcomputing (CISC) microprocessor, a reduced instruction set computing(RISC) microprocessor, a very long instruction word (VLIW)microprocessor, a processor implementing other instruction sets, orother processors implementing a combination of instruction sets. Theprocessor 1002 is configured to execute processing logic in instructionsfor performing the operations and steps discussed herein.

The computer system 1000 may further include a network interface device1010. The computer system 1000 also may or may not include an input1012, configured to receive input and selections to be communicated tothe computer system 1000 when executing instructions. The computersystem 1000 also may or may not include an output 1014, including butnot limited to a display, a video display unit (e.g., a liquid crystaldisplay (LCD) or a cathode ray tube (CRT)), an alphanumeric input device(e.g., a keyboard), and/or a cursor control device (e.g., a mouse).

The computer system 1000 may or may not include a data storage devicethat includes instructions 1016 stored in a computer-readable medium1018. The instructions 1016 may also reside, completely or at leastpartially, within the main memory 1004 and/or within the processor 1002during execution thereof by the computer system 1000, the main memory1004 and the processor 1002 also constituting computer-readable medium.The instructions 1016 may further be transmitted or received over anetwork 1020 via the network interface device 1010.

While the computer-readable medium 1018 is shown in an exemplaryembodiment to be a single medium, the term “computer-readable medium”should be taken to include a single medium or multiple media (e.g., acentralized or distributed database, and/or associated caches andservers) that store the one or more sets of instructions. The term“computer-readable medium” shall also be taken to include any mediumthat is capable of storing, encoding, or carrying a set of instructionsfor execution by the processing device and that cause the processingdevice to perform any one or more of the methodologies of theembodiments disclosed herein. The term “computer-readable medium” shallaccordingly be taken to include, but not be limited to, solid-statememories, optical medium, and magnetic medium.

The embodiments disclosed herein include various steps. The steps of theembodiments disclosed herein may be formed by hardware components or maybe embodied in machine-executable instructions, which may be used tocause a general-purpose or special-purpose processor programmed with theinstructions to perform the steps. Alternatively, the steps may beperformed by a combination of hardware and software.

The embodiments disclosed herein may be provided as a computer programproduct, or software, that may include a machine-readable medium (orcomputer-readable medium) having stored thereon instructions, which maybe used to program a computer system (or other electronic devices) toperform a process according to the embodiments disclosed herein. Amachine-readable medium includes any mechanism for storing ortransmitting information in a form readable by a machine (e.g., acomputer). For example, a machine-readable medium includes: amachine-readable storage medium (e.g., ROM, random access memory(“RAM”), a magnetic disk storage medium, an optical storage medium,flash memory devices, etc.); and the like.

Unless otherwise expressly stated, it is in no way intended that anymethod set forth herein be construed as requiring that its steps beperformed in a specific order. Accordingly, where a method claim doesnot actually recite an order to be followed by its steps, or it is nototherwise specifically stated in the claims or descriptions that thesteps are to be limited to a specific order, it is in no way intendedthat any particular order be inferred.

It will be apparent to those skilled in the art that variousmodifications and variations can be made without departing from thespirit or scope of the invention. Since modifications, combinations,sub-combinations and variations of the disclosed embodimentsincorporating the spirit and substance of the invention may occur topersons skilled in the art, the invention should be construed to includeeverything within the scope of the appended claims and theirequivalents.

What is claimed is:
 1. A method for optimizing radio frequency (RF)coverage in remote unit coverage areas in a wireless distribution system(WDS), comprising: for at least one selected remote unit groupcomprising two or more remote units among a plurality of remote units inthe WDS: instructing a first remote unit in the at least one selectedremote unit group to transmit at least one RF signal; instructing asecond remote unit in the at least one selected remote unit group toreceive the at least one RF signal; determining a first predictiondeviation at the second remote unit based on a difference between the atleast one RF signal received at the second remote unit and the at leastone RF signal predicted to be received at the second remote unit;instructing a third remote unit in the at least one selected remote unitgroup to receive the at least one RF signal; determining a secondprediction deviation at the third remote unit based on a differencebetween the at least one RF signal received at the third remote unit andthe at least one RF signal predicted to be received at the third remoteunit; and determining one or more correction factors for one or moreselected correction points located within an area defined by the atleast one selected remote unit group based on the first predictiondeviation and the second prediction deviation.
 2. The method of claim 1,further comprising: for the at least one selected remote unit groupcomprising two or more remote units among the plurality of remote units:instructing the first remote unit in the at least one selected remoteunit group to transmit the at least one RF signal at a first actualpower level; instructing the second remote unit in the at least oneselected remote unit group to receive the at least one RF signal at asecond actual power level; determining a first power predictiondeviation at the second remote unit based on a difference between thereceived second actual power level and a first predicted receiving powerlevel at the second remote unit; instructing the third remote unit inthe at least one selected remote unit group to receive the at least oneRF signal at a third actual power level; determining a second powerprediction deviation at the third remote unit based on a differencebetween the received third actual power level and a second predictedreceiving power level at the third remote unit; and determining one ormore power correction factors for the one or more selected correctionpoints located within the area defined by the at least one selectedremote unit group based on the first power prediction deviation and thesecond power prediction deviation.
 3. The method of claim 2, furthercomprising adjusting actual power level of the at least one RF signalbased on the determined one or more correction factors.
 4. The method ofclaim 2, further comprising: determining a first actual path loss at thesecond remote unit based on the received second actual power level andthe transmitted first actual power level; determining a first path lossprediction deviation based on a difference between the determined firstactual path loss and a first predicted path loss at the second remoteunit; determining a second actual path loss at the third remote unitbased on the received third actual power level and the transmitted firstactual power level; determining a second path loss prediction deviationbased on a difference between the determined second actual path loss anda second predicted path loss at the third remote unit; and determiningone or more path loss correction factors for the one or more selectedcorrection points based on the determined first path loss predictiondeviation and the determined second path loss prediction deviation. 5.The method of claim 4, further comprising: determining that actual pathlosses are higher than predicted path losses at the one or more selectedcorrection points based on the one or more path loss correction factors;and controlling the first remote unit in the at least one selectedremote unit group to increase the first actual power level of the atleast one RF signal in response to determining that the actual pathlosses are higher than the predicted path losses at the one or moreselected correction points.
 6. The method of claim 4, furthercomprising: determining that actual path losses are lower than predictedpath losses at the one or more selected correction points based on theone or more path loss correction factors; and controlling the firstremote unit in the at least one selected remote unit group to decreasethe first actual power level of the at least one RF signal in responseto determining that the actual path losses are lower than the predictedpath losses at the one or more selected correction points.
 7. The methodof claim 4, further comprising: determining that actual path losses areequal to predicted path losses at the one or more selected correctionpoints based on the one or more path loss correction factors; andcontrolling the first remote unit in the at least one selected remoteunit group to maintain the first actual power level of the at least oneRF signal in response to determining that the actual path losses areequal to the predicted path losses at the one or more selectedcorrection points.
 8. The method of claim 2, further comprisingdetermining one or more power correction factors for the one or moreselected correction points based on the determined first powerprediction deviation and the determined second power predictiondeviation.
 9. The method of claim 8, further comprising: determiningthat actual power levels are higher than predicted receiving powerlevels at the one or more selected correction points based on the one ormore power correction factors; and controlling the first remote unit inthe at least one selected remote unit group to decrease the first actualpower level of the at least one RF signal in response to determiningthat the actual power levels are higher than the predicted receivingpower levels at the one or more selected correction points.
 10. Themethod of claim 8, further comprising: determining that actual powerlevels are lower than predicted receiving power levels at the one ormore selected correction points based on the one or more powercorrection factors; and controlling the first remote unit in the atleast one selected remote unit group to increase the first actual powerlevel of the at least one RF signal in response to determining that theactual power levels are lower than the predicted receiving power levelsat the one or more selected correction points.
 11. The method of claim8, further comprising: determining that actual power levels are equal topredicted receiving power levels at the one or more selected correctionpoints based on the one or more power correction factors; andcontrolling the first remote unit in the at least one selected remoteunit group to maintain the first actual power level of the at least oneRF signal in response to determining that the actual power levels areequal to the predicted receiving power levels at the one or moreselected correction points.
 12. The method of claim 2, furthercomprising configuring the first remote unit in the at least oneselected remote unit group to transmit the at least one RF signalcomprising at least one non-modulated continuous wave signal.
 13. Themethod of claim 12, further comprising configuring the second remoteunit and the third remote unit to receive the at least one non-modulatedcontinuous wave signal at a defined RF filter bandwidth.
 14. The methodof claim 2, further comprising: instructing the first remote unit totransmit the at least one RF signal in a downlink frequency range of atleast one of the second remote unit and the third remote unit in the atleast one selected remote unit group; and instructing the at least oneof the second remote unit and the third remote unit to receive the atleast one RF signal in a listening mode in the downlink frequency range.15. The method of claim 2, further comprising: instructing the firstremote unit to transmit the at least one RF signal in an uplinkfrequency range of at least one of the second remote unit and the thirdremote unit in the at least one selected remote unit group; andinstructing the at least one of the second remote unit and the thirdremote unit to receive the at least one RF signal in a listening mode inthe uplink frequency range.
 16. The method of claim 2, furthercomprising configuring the first remote unit to transmit the at leastone RF signal to the second remote unit and the third remote unit in theat least one selected remote unit group concurrently.
 17. The method ofclaim 16, further comprising determining the first power predictiondeviation by subtracting the first predicted receiving power level fromthe second actual power level.
 18. The method of claim 16, furthercomprising determining the second power prediction deviation bysubtracting the second predicted receiving power level from the thirdactual power level.
 19. The method of claim 2, further comprisingtransmitting the at least one RF signal that comprises a plurality ofnon-coherent frequencies corresponding to a plurality of assigned weightfactors, respectively.
 20. The method of claim 19, further comprising:receiving the at least one RF signal by the second remote unit in theplurality of non-coherent frequencies; and determining the first powerprediction deviation based on the plurality of assigned weight factorscorresponding to the plurality of non-coherent frequencies.
 21. Themethod of claim 19, further comprising: receiving the at least one RFsignal by the third remote unit in the plurality of non-coherentfrequencies; and determining the second power prediction deviation basedon the plurality of assigned weight factors corresponding to theplurality of non-coherent frequencies.
 22. The method of claim 2,further comprising locating the first remote unit, the second remoteunit, and the third remote unit in the at least one selected remote unitgroup at a first height from a ground level.
 23. The method of claim 22,further comprising determining a correction factor for a selectedcorrection point located at a second height lower than the first heightbased on the first power prediction deviation and the second powerprediction deviation.